The invention relates to a charge-coupled imaging device comprising a semiconductor body which is provided at a surface with a two-dimensional matrix of photosensitive elements which are arranged in rows and columns and in which, dependent upon the intensity of incident electromagnetic radiation, electric charge is generated which can be transferred in the form of discrete charge packets via a system of parallel transport lines in the form of charge-coupled devices in the column direction towards a readout register in the form of a charge-coupled device for transferring charge packets in a direction parallel to the rows.
Such a device is for example known from the article "Tektronics Four Quadrant Readout 1024 * 1024 CCD Imager: First Test Results" by Delamere et.al., published in Proc. Spie Vol. 1071 Optical Sensors and Electronic Photography (1989), pp. 197/202. In said article a description is given of a CCD imaging device which comprises a number of adjacent vertical CCD-channels which form the matrix of photosensitive elements. The upper side and the lower side of the matrix are each provided with two horizontal readout registers which are each connected to one of 4 output amplifiers. When the device is in operation, in the integration period an image is converted to a pattern of charge packets of charge carriers of a certain type, for example electrons in the case of an n-channel CCD. Subsequently, the charge packets in the various quadrants can be transferred via the vertical channels to the associated horizontal readout register to be read out. The use of four readout registers permits the stored information to be read out very rapidly. This is very important, particularly, yet not exclusively, when the number of photosensitive elements is very large, such as in "Full Frame" imaging devices.
In CCD imaging devices in general, it may be necessary to provide zones in the matrix with an electrical connection to supply or drain current, or to apply a specific voltage. As will be apparent from the description of the drawings given below, this situation occurs when the imaging device must be protected against overexposure (anti-blooming), requiring electric charge generated in the matrix to be drained. In the case of imaging devices which are provided with a horizontal readout register on only one side of the matrix, for example the lower side, such connections can be provided at the upper side of the matrix where there is no horizontal readout register. Of course, in this case the same problems as described above with respect to the four-quadrant imaging device would occur if it were necessary, for example, to provide such electrical connections at the lower side.